It was written at feverish speed after Stevenson woke from a dream. He produced a draft that he showed to his wife who, it is thought, prompted him to burn it, though he brought it back to life, rewriting it twice in six weeks.
The 1885 manuscript which will go to the British Library reflects his obsessiveness. As ideas flowed, so did his pen, ignoring occasional grammatical and spelling mistakes as he struggled to get it all down.
Jamie Andrews, the exhibition's co-curator, said: "This is an incredibly interesting active draft. There's a sense of it stemming from a dream, the depths of the self. So the idea of this primal eruption of text is certainly there in the story, but then to publish something Stevenson really had to work it through to make it into that final version."
Andrews believes that explicit references to Hyde's sexual "vices" might have concerned Stevenson's wife because of his reputation as a writer of children's novels.
Andrews said of this draft: "It's a lot darker than the final version. This is the great psychological novel about a divided city and a divided self."
He added that, because Stevenson was hard up, it was suggested that he should write a chilling shocker, as they called them.
Commenting on Stevenson's softening of his original ideas, Andrews said that sometimes individual words, lines or paragraphs were deleted. "There's a sense of bits being too sensitive to be published." For example, Stevenson deleted the following line: "From an early age, however, I became in secret the slave of certain appetites." He replaced it with: "And indeed the worst of my faults was a certain impatient gaiety of disposition ... hard to reconcile with my imperious desire to carry my head high, and wear a more than commonly grave countenance before the public."
One of the exhibition themes examines how British landscapes permeate great literary works. Marking Dickens's bicentenary are pages from Our Mutual Friend - its first public show in Britain. Tanya Kirk, exhibition co-curator, said Dickens presented the Thames as a menacingly gothic place sustaining life but bringing death.
The pages to be displayed at the British Library come from the instalment saved from an 1865 rail crash by Dickens, who was hailed a hero for his role in rescuing the injured. The carriage in which Dickens was travelling through Kent was derailed and suspended over a collapsed bridge.
He risked his life in clambering back into the wreckage for passengers and the manuscript, its pages spattered with stains.
The exhibition will celebrate a superlative collection of literary works at the British Library spanning more than 1000 years by writers from Chaucer to Hanif Kureishi. Exhibits will include letters penned by John Keats, Charlotte Bronte and Ted Hughes never before displayed.
- Observer